Perform a research protocol developed by the National Institute of Child Health and Human Development to conduct a longitudinal study of fetal growth and perinatal outcome of women at risk of delivering small-for-gestational-age birthsusing a geographically-based population of women documented through a system of vital records registration or comparablesystem who are expecting their second or third child. Data will be obtained on sociodemographic, nutritional, lifestyle, prenatal, labor, delivery, and postnatal care.